Also as part of the screening tests, you will have an electrocardiogram (ECG)a test that measures the electrical activity of the heart). You will have a bone marrow biopsy and aspiration within 3 months of starting the study (or within 2 weeks of starting the study, if you have received treatment for SM). To collect a bone marrow biopsy/aspirate, an area of the hip bone is numbed with anesthetic, and a small amount of bone marrow and bone is withdrawn through a large needle. The bone marrow samples will be used not only to check the status of the disease, but also for a routine test to see if there is a mutation (change) in a certain gene. If your doctor feels it is necessary, you may need to have additional screening tests (such as a bone scan) to check the status of the disease.